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/*
** Copyright (c) 2012 The Khronos Group Inc.
**
** Permission is hereby granted, free of charge, to any person obtaining a
** copy of this software and/or associated documentation files (the
** "Materials"), to deal in the Materials without restriction, including
** without limitation the rights to use, copy, modify, merge, publish,
** distribute, sublicense, and/or sell copies of the Materials, and to
** permit persons to whom the Materials are furnished to do so, subject to
** the following conditions:
**
** The above copyright notice and this permission notice shall be included
** in all copies or substantial portions of the Materials.
**
** THE MATERIALS ARE PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
** EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
** MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
** IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
** CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
** MATERIALS OR THE USE OR OTHER DEALINGS IN THE MATERIALS.
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-->

<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <link rel="stylesheet" href="../../resources/js-test-style.css"/>
        <script src="../../resources/js-test-pre.js"></script>
        <script src="../resources/webgl-test.js"></script>
        <script src="../resources/webgl-test-utils.js"></script>
        <script id='vshader' type='x-shader'>
            attribute vec4 a;
            attribute vec2 p;
            void main() {
                gl_Position = vec4(p.x + a.x + a.y + a.z + a.w, p.y, 0.0, 1.0);
            }
        </script>
        <script id='fshader' type='x-shader'>
            precision mediump float;
            void main() {
                gl_FragColor = vec4(1.0, 0.0, 0.0, 1.0);
            }
        </script>
        <script>
            "use strict";
            function checkRedPortion(gl, w, low, high) {
                var buf = new Uint8Array(w * w * 4);
                gl.readPixels(0, 0, w, w, gl.RGBA, gl.UNSIGNED_BYTE, buf);
                var i = 0;
                for (; i < w; ++i) {
                    if (buf[i * 4 + 0] == 255 && buf[i * 4 + 1] == 0 && buf[i * 4 + 2] == 0 && buf[i * 4 + 3] == 255) {
                        break;
                    }
                }
                return low <= i && i <= high;
            }

            function runTest() {
                var wtu = WebGLTestUtils;
                var gl = wtu.create3DContext('testbed', { preserveDrawingBuffer : true });
                if (!gl) {
                    testFailed('could not create context');
                    return;
                }
                var program = wtu.setupProgram(gl, ['vshader', 'fshader'], ['p', 'a'])

                gl.enableVertexAttribArray(gl.p);
                var pos = gl.createBuffer();
                pos.type = gl.FLOAT;
                pos.size = 2;
                pos.num = 4;
                gl.bindBuffer(gl.ARRAY_BUFFER, pos);
                gl.bufferData(gl.ARRAY_BUFFER, new Float32Array([-1, -1, 1, -1, -1, 1, 1, 1]), gl.STATIC_DRAW);

                gl.vertexAttribPointer(0, pos.size, pos.type, false, 0, 0);

                debug('Test vertexAttrib[1..4]fv by setting different combinations that add up to 1.5 and use that when rendering.');
                var vals = [[0.5], [0.1,0.4], [0.2,-0.2,0.5], [-1.0,0.3,0.2,2.0]];

                for (var j = 0; j < 4; ++j) {
                    gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
                    gl['vertexAttrib' + (j+1) + 'fv'](1, vals[j]);
                    gl.drawArrays(gl.TRIANGLE_STRIP, 0, pos.num);

                    if (checkRedPortion(gl, 50, 50 * 0.7, 50 * 0.8)) {
                        testPassed('Attribute of size ' + (j+1) + ' was set correctly');
                    } else {
                        testFailed('Attribute of size ' + (j+1) + ' was not set correctly');
                    }
                }
            }
        </script>
    </head>
    <body>
        <canvas id="testbed" width="50" height="50"></canvas>
        <div id="description"></div>
        <div id="console"></div>
        <script>
            "use strict";
            description('Verify that using constant attributes works.');
            runTest();
            var successfullyParsed = true;
        </script>
        <script src="../../resources/js-test-post.js"></script>
    </body>
</html>
